1. Field of the Invention
The present invention is directed to stringed musical instruments, and more particularly to stringed musical instruments with improved harmonic generation.
2. Description of the Related Art
An important characteristic of a musical instrument is its tone. A tone may be considered as a particular combination of a fundamental frequency and accompanying harmonics, each with a particular amplitude and phase. The combination of these harmonics gives an instrument its tone. For instance, an “A” note played on a violin will sound different from an “A” note played on a guitar, even though both “A” notes have a fundamental frequency of 440 Hz, because a violin has a different characteristic tone from a guitar. Likewise, a pure sine wave at 440 Hz, which has no accompanying harmonics, will sound different from an “A” played on either a violin or a guitar. Put simply, it is the harmonics accompanying each note that give an instrument its characteristic sound, or tone. In general, the more harmonics that accompany each note, the more complex the tone of the instrument, and the more pleasing the sound that is perceived by the listener.
In the early history of stringed instruments, the volume emitted from an instrument typically was not great. An instrument might have been played in the court of a member of royalty, and only need have produced enough sound for the handful of people that might have been present. As time passed, and the venues for music increased in size to modern day concert halls, the required volume from musical instruments increased as well. Instruments evolved to be louder, producing more volume and allowing their sound to project into larger and larger venues. For stringed instruments, the way to produce a louder sound was to increase the string tension and use a larger acoustical cavity and playing table.
Although the newer stringed instruments were indeed louder, they suffered from a simplicity of tone. For example, the modern-day guitar may produce enough sound to reach the back row of a large concert hall, but the sound it produces is dominated by its fundamental frequency, and is largely devoid of the accompanying strong harmonics that would increase the richness of its tone. Some might say that the modern-day stringed instruments lack the richness in tone that was present in their predecessors, despite being much louder than their predecessors. In addition, the newer instruments suffered from a lack of sustain, which is the desirable “ringing” of an instrument after a note is played.
Many of the stringed instruments, both antiquated and current, have several elements in common. The strings are fastened on the top side of the instrument, and generally extend along a neck. The tension of each string is adjustable at one or both ends, so that the instrument may be tuned. The strings are mechanically coupled by a bridge to a top plate, which is sometimes called a playing table. Typically, the top plate is substantially flat, although it may be domed or arched in places with respect to a coplanar edge, and may optionally have one or more holes in it that allow air to pass into and out of the instrument. Opposite the top plate is a back plate, which is also typically flat and with its mass substantially evenly distributed, although it too may be domed or arched in places with respect to a coplanar edge. While the back plate may be made from a single piece of wood, typically it is made from two pieces that are glued together, and the glue joint is reinforced by strips or cleats of soft and light wood. Braces normal to the seam and running between the strips or cleats may be used to improve the structural integrity of the back plate. The top plate and the back plate are joined at their perimeters by a rib or ribs. Typically the rib is produced as a long, thin, rectangular piece of wood veneer or laminate of essentially constant width and thickness, which is bent into shape to trace the outline of the top and back plates, and glued. Once secured, the rib is substantially perpendicular to both the top and back plates along the entirety of both seams.
Although modem stringed instruments individually lack rich and complex tonal color, pleasing tonal color may be achieved in an acoustically correct concert hall when essentially identical instruments identically tuned are played with precision by professional musicians. Unfortunately, differences between instruments of the same type and their tuning, as well as the understandable limitations of many non-professional musicians, result in the poor tonal color experienced in many performances.
Accordingly, there exists a need for a stringed instrument that has the volume level of modern-day instruments, but has an increased richness in tone, characterized by an increase in the harmonics that accompany each note. The stringed instrument should also have a large degree of sustain. Such a stringed instrument would be able to produce a richer, more complex sound than its current counterparts, while producing enough volume to adequately fill a large concert venue, thereby eliminating or reducing the need to rely on multiple instruments and the properties of the concert hall to achieve full tonal color.